Locking device for electrical connectors



A. 26,1946. J. F. OBRIEN LOCKING DEVICE FOR ELECTRICAL CONNECTORS Filed on. 14, 1942 Patented Aug. 20, 1946 LOCKING DEVICE FOR. ELECTRICAL CONNECTORS Joseph F. OBrien, Jersey City, N. 3., assignor to I John B. Pierce Foundation, New York, N. Y.,

a corporation of New York Application October 14, 1942, Serial No. 461,948

Claims. 1

This invention relates to lockin devices for electrical connectors.

In particular, the invention relates to improved means for securement of an electrical outlet plu to an outlet receptacle to prevent the accidental separation thereof, and to provide strain relief means to eliminate strain on the connections of the electric wire at the outlet plug.

It is an object of the invention to provide improved means for releasably securing an electric outlet plug to an outlet fixture.

It is an object of the invention to provide means whereby an outlet plug may be attached to an outlet receptacle in such manner that the plug cannot be pulled out of contact with the receptacle in normal usage, but will be released in the event of an abnormal pull on the wire or cable which might otherwise damage the cable or break its connection with the outlet plug.

It is an object of the invention to provide an outlet plug securement means which will not interfere with the use of the plug with standard or conventional receptacles.

It is an object of the invention to provide an outlet plug securement means which can be used with a standar plu and which will permit the securement of said plug without the necessity of twisting the plug or any complementary locking device on the plug or the receptacle.

According to a preferred form of the invention, I provide colla means adapted for securement about the body of an electric attachment plug, said collar means having spring members having outwardly extending terminals for engagement with a looking or anchor plate secured to the outlet receptacle.

, Preferably, the looking or anchor plate has pockets or equivalent formed therein, into which the terminals of the spring members fit, thereby to hold the outlet plug in operative association with the outlet receptacle under all normal conditions of use.

It is a featur of the invention that the spring members which are carried b the plug-provided member do not extend beyond the face of the outlet plug, i. e., the blade-provided plug member from which its blades project, thereb permitting the use of an outlet plug equipped with my invention with conventional electric outlet receptacles.

In the accompanying drawing:

Fig. 1 is an elevation, partly in section, showing an outlet plug secured to an electri receptacle pursuant to a preferred form of the invention;

Fig. 2 is a section, taken on lines Z --2;of Fig.

2 1, of the cooperating looking or anchor plate of the outlet receptacle;

Fig. 3 is a bottom plan view of an outlet plug fitted with my improved locking means; 1 a

Fig. 4 is a plan view of a section of electrica conduit at the outlet receptacle portion thereof, and having mounted thereon one form of looking or anchor plate;

Fig. 5 is a vertical elevation of an outlet plug equipped with a preferred embodiment of the invention;

Fig. 6 is similar to Fig. 4, illustrating a second form of plug looking or anchor plate; and

Fig. 7 is a bottom view of the locking or ancho plate of Fig. 4.

Referring to the drawing, an attachment plug I!) having a conventional electric cord connection or wire cable II is shown in operative position with respect to an outlet-provided conduit I2, and removably secured in such position by the plug lock I4 and anchor or locking plate I5.

The conduit I2 may be of any conventional cross-section, having outlet provisions including a fiat upper surface against which the face of the attachment plug I0 may abut firmly. In the form illustrated in the drawing, the conduit I2 is rectangular in shape, as disclosed and claimed in U. S. Patent No. 2,239,652, entitled Electrical unit, of which I am a joint patentee.

The anchor or looking plate I5 is onveniently formed from stamped metal. For a rectangular conduit, the anchor I5 includes side walls I6 of triangular contour as shown in Fig. 1, which terminate in inwardly turned flanges II overlying th rear wall of the conduit I2, see Fig. -7. Said flanges I! may include members IIa which overlie the outer rear wall of the conduit I2 and ,a countersunk portion I'Ib adapted to fit within a groove in the rear wall of said conduit I2 to se- I cure the anchor or locking plate I5 against lateral movement along the conduit.

Preferably, the side walls I6 of said anchor or locking plate I5 are springable, to engage the sides of the conduit I2 snugly.

The respective side walls I6 of anchor I5 are interconnected by transverse end elements I8, see Fig. 4, suitably spaced to provide an opening of ample area to expose the plug openings and to accommodate an attachment plug of maximum conventional size. The center portions of the end elements I8 are struck upwardly to provide pockets 20, in mutual alignment.

In the embodiment of Figs. 1, 2, 4 and 7, the anchor or locking plate I5 is held in position by the snug embrace of side members I6 with the conduit walls l2 and the engagement of the depressed portion l'lb with a groove or the like in said conduit.

According to the embodiment of Fig. 6, end elements l8 are provided with ears 2| through which screws may pass into suitable tapped openings in the conduit l2, thereby permanently securing the anchor member against the possibility of accidental removal or displacement,

Referring to Figs. 3 and 5, the plug lock M includes members of similar shape but opposite hand, each member having a relatively large, substantially semi-circular strap 24 for securement about the body of the plug l0, and a semi-circular collar 25, said strap and collar being connected by the bridge 26.

Secured to each of said bridges 26, desirably to the under side thereof, are spring members 21, the free ends of which extend through a slot 28 in each of the respective bridges to present an external springable portion which may be grasped and squeezed inwardly to an extent permitting the hooked ends 3%! thereof to clear the end walls of the pockets 29.

The respective straps 24 of the plug look It may be clamped about the plug [0 as by the illustrated screws, and the collar portion 25 clamped tightly about the conductor wire H to serve a a strain relief and prevent a disconnection of the Wire cable I I with the terminals of the outlet plug I0 in the event that a strong pull is exerted on the wire. y

In employing the invention, the spring members 21 carried by the blade-provided plug member are squeezed together as aforesaid, whereupon such blade-provided plug member may be inserted directly into the indicated apertures cf the outlet, following which upon manual release of the spring members 21 their outwardly directed hook free ends 30 are caused to engage beneath the top walls of the pockets 20.

Desirably, in the circumstance of an abnormal pull exerted upon the wire cable either the upper wall surface of the pockets 2B, or the outwardly extending ends 30 of springs 21, or both, should be so sloped that a strong outward pull applied to the cable H will initiate a camming action of the ends of spring members 21 against the pockets 20 and urge the said spring members inwardly to release from pockets 20, whereupon the plug 10 will be released from the receptacle before damage can be done to the cord II or the connection of the conductors of said cord with the outlet plug 10.

It will be observed that embodiment of the invention are particularly applicable to bladeprovided electrical plugs in association with electrical outlets or receptacles having a substantially flat face in which their blade-receiving apertures are located, thus affording the aflixing to such substantially flat facea substantially fiat anchor or looking plate, the pockets of which are arranged in close contiguity with such fiat face of the outlet whereby the spring members having springable hook free ends are disposed within the zone of the bodyof the blade-provided plug, thereby facilitating the manual release of such springable members from such pockets of the locking plate concomitant with the act of grasping theplug in the normal manner of withdrawing its blades from the apertures of the outlet or receptacle when it is desirable to disconnect the plug with respect to the outlet or receptacle.

Whereas I have described my invention by reference to specific forms thereof, it will be understood that many change and modifications may be made provided they do not depart from the scope of the claims.

I claim:

1. Means for releasably securing an attachment plug to an outlet receptacle, comprising the combination with an anchor plate having side walls resiliently embracing the side walls of the outlet receptacle, flange means engaging with the rear walls thereof, and spaced pocket means disposed above the face of the receptacle, of a strap for securement about the body of the attachment plug and spring means operatively associated with said strap and having free, springable ends terminating in outwardly directed hook members for engagement beneath the pocket of said anchor plate.

2. Means for removably securing an attachment plug to an outlet receptacle, comprising the combination with an anchor plate having side walls resiliently embracing the side walls of the outlet receptacle, flange mean engaging with the rear walls thereof, and spaced pocket means disposed above the face of the receptacle, of a strap for securement about the body of the attachment plug, member's extending upwardly therefrom, and spring means fastened at one end to the underside of said members and having free, springable ends terminating in outwardly directed hook member for engagement beneath the pockets of said anchor plate.

3. Means for removably securing an attachment plug to an outlet receptacle, comprising: an anchor plate having side Walls for tightly embracing the side walls of said outlet receptacle, said side walls terminating in inwardly directed flanges for gripping the rear wall of said outlet receptacle, said side walls being connected by spaced transverse members extending across the face of said outlet receptacle, each transverse member having a pocket formed therein; and attachment plug means including opposed substantially semi-circular strap portions adapted collectively to encircle the body of said plug for securement thereto, opposed, substantially semicircular collar portions adapted collectively to securely embrace a wiring erving said attachment plug, bridge means connecting the respective strap and collar portions, each said bridge means having a slot intermediate the ends thereof, and spring means secured to each said bridge means on the underside thereof and having free, springable ends extending through said slot thereof, aid springable ends terminating in outwardly extending hook portions disposed substantially in the plane of the face of the attachment plug for engagement with the pockets of the respective transverse end members of the ancho plate.

4. Means for removably securing an attachment plug to an outlet receptacle, comprising the combination with an anchor plate having side walls resiliently embracing the side walls of the outlet receptacle, flange mean engaging with the rear walls thereof, and spaced pocket means disposed above the face of the receptacle, of a strap for securement about the body of the attachment plug, members extending upwardly therefrom, and spring means fastened at one end to the underside of said members and projecting through said members to the outside thereof, said spring mean having springable ends terminating in outwardly directed hook members for engagement beneath the pockets of said anchor plate.

5. Means for releasably securing a blade-provided electrical plug to an aperture-provided electrical receptacle or other outlet, comprising: a locking plate arranged to be afiixed to the aperture-provided face of such outlet, said locking plate having mutually spaced pockets; a strap arranged to be fixedly secured to such bladeprovided plug about the body thereof; members extending from said strap; spring members secured to said members and having free springable hook end portions arranged for resilient insertion into said pockets.

6. Means for releasably securing a blade-provided electrical plug to an aperture-provided electrical receptacle or other outlet, comprising: a locking plate arranged to be afiixed to the aperture-provided face of such outlet, said locking plate having mutually spaced pockets; a strap arranged to be fixedly secured to such bladeprovided plug about the body thereof; members extending from said strap; spring members fixedly secured at their one ends to said members and having free springable hook end portions arranged for resilient insertion into said pockets, said spring members being disposed within the zone of the body of such blade-provided plug.

7. Means for releasably securing a blade-provided electrical plug to an electrical receptacle or other outlet having a fiat face provided with blade-receiving apertures, comprising: a sub stantially fiat locking plate arranged to be affixed to the substantially fiat face of such electrical outlet, said locking plate having mutually spaced pockets; a strap arranged to be secured to such blade-provided plug about the body thereof; members supported by said strap in fixed relation with said blade-provided plug; spring members secured to said members and having free springable hook end portions arranged for resilient insertion into said pockets.

8. Means for releasably securing a blade-provided electrical plug to an electrical receptacle or other outlet having a flat face provided with blade-receiving apertures, comprising: a substantially flat lockingplate arranged to be affixed to the substantially fiat face of such electrical outlet, said locking plate having mutually spaced pockets; a strap arranged to be fixedly secured to such blade-provided plug about the body thereof; members supported by said strap; spring members secured to aid members and having free springable hook end portions arranged for resilient insertion into said pockets, said spring members being disposed within the zone of the body of such blade-provided plug.

9. A blade-provided electrical plug having a body provided with a substantially flat face; electrical blades projecting from said body at said flat face; strap means secured in substantially fixed relation with said body; members fixedly supported by said strap means, spring members secured to said members and having free springable hook end portions, said spring members extending within the zone of said body.

10. Means for releasably securing a bladeprovided electrical plug to an electrical receptacle or other outlet having a substantially fiat face and blade-receiving apertures in such face, comprising: a locking plate arranged to be affixed to such receptacle adjacent such substantially flat face and having locking means; spring means secured at one end thereof in fixed relation with and within the zone of the body of such blade-provided electrical plug, said spring means having springable free end means arranged to cooperate with said locking means of said locking plate for releasable connection therewith.

JOSEPH F. OBRIEN. 

